Apparatus and method for transmitting feedback information in wireless communication systems

ABSTRACT

An apparatus and a method for transmitting HARQ feedback information in a wireless communication system are provided. In so doing, the method for transmitting the HARQ feedback information in a receiving end includes confirming the number of packets received from a transmitting end, and when receiving a reference number of packets from the transmitting end, transmitting to the transmitting end a feedback signal comprising HARQ feedback information for the reference number of the packets.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to a wireless communicationsystem. More particularly, the present invention relates to an apparatusand a method for transmitting Hybrid Automatic Repeat reQuest (HARQ)feedback information in a wireless communication system.

BACKGROUND OF THE INVENTION

A wireless communication system can have an error in transmission dataaccording to channel status of a radio resource carrying the data.Hence, to raise transmission reliability, the wireless communicationsystem controls and corrects the data error using HARQ as shown in FIG.1.

FIG. 1 depicts a method for transmitting HARQ feedback information in aconventional wireless communication system.

As shown in FIG. 1, when a transmitting end 100 transmits packets to areceiving end 110, the receiving end 110 transmits HARQ feedbackinformation of the received packets to the transmitting end 100 afterTransmission Time Interval (x TTIs) 120 pass from the packet receptiontime. Here, the HARQ feedback information includes ACK indicatingreception success information of the packet, NACK indicating receptionfailure information of the packet, and Discontinuous Transmission (DTX)indicating that the packet reception is not confirmed.

When the transmitting end 100 receives the NACK for a packet 1, thetransmitting end 100 retransmits the packet 1 to the receiving end 110after a retransmission time interval (y TTIs) 122 passes from the NACKreception time.

Using the HARQ scheme as above, the receiving end 110 transmits the HARQfeedback information to the transmitting end 100 for the packetsreceived from the transmitting end 100. In this case, the receiving endneeds to activate 130 a transmission power amplifier to transmit theHARQ feedback information though there is no data to transmit through anuplink, and thus power is consumed inefficiently.

Thus, the wireless communication system requires a method for reducingthe inefficient power consumption according to the HARQ feedbackinformation transmission in the receiving end.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies of the prior art, it is aprimary aspect of the present invention to provide an apparatus and amethod for transmitting HARQ feedback information in a receiving end ofa wireless communication system.

Another aspect of the present invention is to provide an apparatus and amethod for reducing power consumption according to HARQ feedbackinformation transmission in a receiving end of a wireless communicationsystem.

Yet another aspect of the present invention is to provide an apparatusand a method for transmitting HARQ feedback information for a pluralityof received packets using a single feedback signal in a receiving end ofa wireless communication system.

Still another aspect of the present invention is to provide an apparatusand a method for retransmitting a packet by considering HARQ feedbackinformation of a plurality of packets confirmed in a single feedbacksignal, in a transmitting end of a wireless communication system.

A further aspect of the present invention is to provide an apparatus anda method for selectively using a plurality of feedback modes in awireless communication system.

According to one aspect of the present invention, a method fortransmitting HARQ feedback information in a receiving end of a wirelesscommunication system includes confirming the number of packets receivedfrom a transmitting end, and when receiving a reference number ofpackets from the transmitting end, transmitting to the transmitting enda feedback signal comprising HARQ feedback information for the referencenumber of the packets.

According to another aspect of the present invention, a method forconfirming HARQ feedback information in a transmitting end of a wirelesscommunication system includes transmitting a packet to a receiving end;and when receiving a feedback signal from the receiving end, confirmingHARQ feedback information for a reference number of packets in thefeedback signal.

According to yet another aspect of the present invention, an apparatusfor transmitting HARQ feedback information in a receiving end of awireless communication system includes a receiver for receiving apacket; a controller for controlling to confirm the number of packetsreceived from a transmitting end through the receiver, and whenreceiving a reference number of packets from the transmitting end, totransmit to the transmitting end a feedback signal comprising HARQfeedback information for the reference number of the packets; and atransmitter for transmitting the feedback signal to the transmittingend.

According to still another aspect of the present invention, an apparatusfor confirming HARQ feedback information in a transmitting end of awireless communication system includes a transmitter for transmitting apacket to a receiving end; a receiver for receiving a feedback signalfrom the receiving end; and a controller for, when receiving thefeedback signal from the receiving end, confirming HARQ feedbackinformation for a reference number of packets in the feedback signal.

Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainexemplary embodiments of the present invention will be more apparentfrom the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates a method for transmitting HARQ feedback informationin a conventional wireless communication system;

FIG. 2 illustrates a method for transmitting HARQ feedback informationin a wireless communication system according to one exemplary embodimentof the present invention;

FIG. 3 illustrates a method for transmitting the HARQ feedbackinformation in a receiving end according to one exemplary embodiment ofthe present invention;

FIG. 4 illustrates a method for confirming the HARQ feedback informationin a transmitting end according to one exemplary embodiment of thepresent invention;

FIG. 5 illustrates a method for retransmitting a packet in the wirelesscommunication system according to one exemplary embodiment of thepresent invention;

FIG. 6 illustrates a method for retransmitting the packet in thewireless communication system according to another exemplary embodimentof the present invention;

FIG. 7 illustrates a method for transmitting the HARQ feedbackinformation in the wireless communication system according to anotherexemplary embodiment of the present invention;

FIG. 8 illustrates a method for transmitting the HARQ feedbackinformation in the receiving end according to another exemplaryembodiment of the present invention;

FIG. 9 illustrates a method for confirming the HARQ feedback informationin the transmitting end according to another exemplary embodiment of thepresent invention;

FIG. 10 illustrates a method for switching a feedback mode in thetransmitting end according to an exemplary embodiment of the presentinvention;

FIG. 11 illustrates a method for switching the feedback mode in thereceiving end according to an exemplary embodiment of the presentinvention;

FIG. 12 illustrates the transmitting end according to an exemplaryembodiment of the present invention; and

FIG. 13 illustrates the receiving end according to an exemplaryembodiment of the present invention.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components and structures.

DETAILED DESCRIPTION OF THE INVENTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the embodiments described hereincan be made without departing from the scope and spirit of theinvention. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of theinvention. Accordingly, it should be apparent to those skilled in theart that the following description of exemplary embodiments of thepresent invention is provided for illustration purpose only and not forthe purpose of limiting the invention as defined by the appended claimsand their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

By the term “substantially” it is meant that the recited characteristic,parameter, or value need not be achieved exactly, but that deviations orvariations, including for example, tolerances, measurement error,measurement accuracy limitations and other factors known to those ofskill in the art, may occur in amounts that do not preclude the effectthe characteristic was intended to provide.

Exemplary embodiments of the present invention provide a technique forefficiently transmitting HARQ feedback information in a wirelesscommunication system. Here, HARQ feedback indicates a series ofoperations of a receiving end for reporting the reception status of apacket received from a transmitting end, to the transmitting end. TheHARQ feedback information includes ACK indicating successful receptionof the packet, NACK indicating reception failure of the packet, andDiscontinuous Transmission (DTX) indicating that the packet reception isnot confirmed.

Hereafter, the transmitting end includes a certain node, such as basestation and terminal, for transmitting the packet in a network. Thereceiving end includes a certain node, such as base station andterminal, for receiving the packet from the transmitting end in thenetwork.

FIG. 2 illustrates a method for transmitting HARQ feedback informationin a wireless communication system according to one exemplary embodimentof the present invention.

As shown in FIG. 2, when a transmitting end 200 transmits packets, areceiving end 210 does not transmit HARQ feedback information untilN_(AG)-ary packets are received from the transmitting end 200. Whenreceiving the N_(AG)-ary packets, the receiving end 210 transmits HARQfeedback information of the N_(AG)-ary packets to the transmitting end200 using a single feedback signal after Transmission Time Intervals (xTTIs) 220 elapse from the reception of the N_(AG)-ary packets. Forexample, when N_(AG) is 3, the receiving end 210 transmits the HARQfeedback information of three packets to the transmitting end 200 usingthe single feedback signal after the transmission time interval x TTIs220 elapses from the reception of the three packets. Here, the x TTI canbe set to a first reference value predefined between the transmittingend 200 and the receiving end 210, or to a certain time beyond the firstreference value.

The transmitting end 200 confirms the HARQ feedback information of theN_(AG)-ary packets in the feedback signal received from the receivingend 210. When the receiving end 210 requests packet retransmission, thetransmitting end 200 retransmits the packet requested by the receivingend 210 to retransmit, to the receiving end 210 after a retransmissiontime interval y TTIs 222 elapses from the reception of the feedbacksignal. For example, when the HARQ feedback information of a packet 1 isNACK, the transmitting end 200 recognizes that the receiving end 210requests to retransmit the packet 1. Accordingly, the transmitting end200 retransmits the packet 1 to the receiving end 210 after theretransmission time interval y TTIs 222 elapses from the reception ofthe feedback signal. Herein, the y TTI can be set to a second referencevalue predefined between the transmitting end 200 and the receiving end210, or to a certain time beyond the second reference value.

When the receiving end 210 requests to retransmit a plurality ofpackets, the transmitting end 200 retransmits the corresponding packetsafter the retransmission time interval y TTIs 222 elapses from thereception of the feedback signal. For example, when synchronous HARQ isapplied, the transmitting end 200 sequentially retransmits the packetsin a preset retransmission order after the retransmission time intervaly TTIs 222 elapses from the reception of the feedback signal. In sodoing, the transmitting end 200 may not transmit a control message forthe retransmitted packets. For example, when asynchronous HARQ isapplied, the transmitting end 200 can retransmit the packets at anarbitrary time after the retransmission time interval y TTIs 222 elapsesfrom the reception of the feedback signal. In so doing, the transmittingend 200 transmits the control message including identificationinformation of the retransmitted packets to the receiving end 210.

As such, the receiving end 210 transmits the HARQ feedback informationof the N_(AG)-ary packets to the transmitting end 200 using the singlefeedback signal. In so doing, the receiving end 210 can generate thefeedback signal to indicate the HARQ feedback information of theN_(AG)-ary packets. For example, the receiving end 210 may generate a1-bit feedback signal by logically operating the HARQ feedbackinformation of the N_(AG)-ary packets. For example, the receiving end210 transmits to the transmitting end the 1-bit feedback signalgenerated by applying AND operation to the HARQ feedback information ofthe N_(AG)-ary packets.

FIG. 3 illustrates a method for transmitting the HARQ feedbackinformation in the receiving end according to one exemplary embodimentof the present invention.

Referring to FIG. 3, the receiving end determines whether the packet isreceived from the transmitting end in step 301.

When receiving the packet from the transmitting end, the receiving endupdates (NRE++) the number of the packet receptions (NRE) in step 303.Here, the number of the packet receptions is a variable for determiningthe HARQ feedback transmission time and can be set to 0 as an initialvalue.

In step 305, the receiving end determines whether the number of thepacket receptions is greater than or equal to the number of the feedbackpackets N_(AG) to determine whether to transmit the HARQ feedbackinformation.

When the number of the packet receptions is smaller than the number ofthe feedback packets N_(AG) (NRE<N_(AG)), the receiving end recognizesno HARQ feedback information transmission. Hence, the receiving enddetermines whether the packet is received from the transmitting end instep 301.

By contrast, when the number of the packet receptions is greater than orequal to the number of the feedback packets N_(AG) (NRE≧N_(AG)), thereceiving end recognizes the HARQ feedback information transmission.Hence, the receiving end determines whether the HARQ feedbackinformation transmission time arrives in step 307. For example, thereceiving end determines whether the HARQ feedback informationtransmission time arrives after the transmission time interval x TTIs220 from the reception of the N_(AG)-th packet as shown in FIG. 2. Atthis time, the receiving end initializes the number of the packetreceptions in order to determine whether to transmit the next HARQfeedback information.

When the HARQ feedback information transmission time arrives, thereceiving end transmits the HARQ feedback information of the N_(AG)-arypackets to the transmitting end using the single feedback signal in step309.

Next, the receiving end finishes this algorithm.

In this embodiment, the receiving end receives the N_(AG)-ary packetsand then maintains a standby mode during the transmission time intervalto transmit the HARQ feedback information of the N_(AG)-ary packets. Inso doing, the receiving end may stand by during the transmission timeinterval to transmit the HARQ feedback information of the N_(AG)-arypackets, and receive the packet from the transmitting end throughanother HARQ process as shown in FIG. 3.

When the receiving end transmits the HARQ feedback information of theN_(AG)-ary packets to the transmitting end using the single feedbacksignal as mentioned above, the transmitting end can confirm the HARQfeedback information of the packets as shown in FIG. 4.

FIG. 4 illustrates a method for confirming the HARQ feedback informationin the transmitting end according to one exemplary embodiment of thepresent invention.

Referring to FIG. 4, the transmitting end transmits the packet to thereceiving end in step 401.

After transmitting the packet to the receiving end, the transmitting endupdates (NTR++) the number of the packet transmissions in step 403.Here, the number of the packet transmissions is a variable forconfirming the HARQ feedback transmission time of the receiving end, andcan be set to 0 as the initial value.

In step 405, the transmitting end determines whether the number of thepacket transmissions is greater than or equal to the number of thefeedback packets N_(AG) to confirm the HARQ feedback informationtransmission time of the receiving end.

When the number of the packet transmissions is smaller than the numberof the feedback packets N_(AG) (NTR<N_(AG)), the transmitting endrecognizes no HARQ feedback information transmission of the receivingend. Hence, when having a packet to transmit to the receiving end, thetransmitting end transmits the packet to the receiving end in step 401.

By contrast, when the number of the packet transmissions is greater thanor equal to the number of the feedback packets N_(AG) (NTR≧N_(AG)), thetransmitting end recognizes that the receiving end transmits the HARQfeedback information after the transmission time interval. Hence, thetransmitting end determines whether the feedback signal is received fromthe receiving end in step 407. In so doing, the transmitting endinitializes the number of the packet transmissions to confirm thetransmission time of the next HARQ feedback information of the receivingend.

When receiving the feedback signal from the receiving end, thetransmitting end confirms the HARQ feedback information of theN_(AG)-ary packets in the feedback signal received from the receivingend in step 409.

In step 411, the transmitting end determines whether the receiving endrequests to retransmit a packet. For example, the transmitting enddetermines whether the packets transmitted to the receiving end includesthe packet including the NACK as the HARQ feedback information.

When the receiving end requests to retransmit the packet, thetransmitting end determines whether a retransmission time arrives instep 413. For example, the transmitting end 200 determines whether theretransmission time arrives after the retransmission time interval yTTIs 222 elapses from the reception of the feedback signal as shown inFIG. 2.

When the retransmission time arrives, the transmitting end retransmitsthe packet requested by the receiving end to retransmit, to thereceiving end in step 415. For example, when retransmitting a pluralityof packets using the synchronous HARQ, the transmitting end sequentiallyretransmits the corresponding packets in a preset retransmission orderafter the retransmission time interval passes from the reception of thefeedback signal. In so doing, the transmitting end may not transmit thecontrol message for the retransmitted packets. For example, whenretransmitting a plurality of packets using the asynchronous HARQ, thetransmitting end retransmits the corresponding packets at an arbitrarytime after the retransmission time interval elapses from the receptionof the feedback signal. In so doing, the transmitting end transmits thecontrol message including the identification information of theretransmitted packets to the receiving end.

Next, the transmitting end finishes this algorithm.

In the above embodiment, the transmitting end transmits the N_(AG)-arypackets and then maintains the standby mode until the HARQ feedbackinformation of the N_(AG)-ary packets are received. In so doing, thetransmitting end may stand by until the HARQ feedback information of theN_(AG)-ary packets are received, and transmit the packet to thereceiving end through another HARQ process as shown in FIG. 4.

As above, when the receiving end transmits the HARQ feedback informationof the N_(AG)-ary packets to the transmitting end using the singlefeedback signal, it is important for the receiving end to recognize thereception time of the packet for the transmission time of the feedbacksignal. For example, in case of 3GPP LTE standard, the receiving end canconfirm the packet transmission time from the transmitting end to thereceiving end in Downlink Control Information (DCI) received through aPhysical Downlink Control Channel (PDCCH). However, when the receivingend cannot receive the DCI due to a reception error, the receiving endcannot recognize the packet reception time and can make an error inrecognizing the feedback signal transmission time. Hence, thetransmitting end adds a packet index to the control informationindicating whether the packet is transmitted to the receiving end, andtransmits to the receiving end as shown in FIG. 5 and FIG. 6. Here, thepacket index (Downlink Assignment Index (DAI)) is in a size indicatingthe number of the packets carrying the HARQ feedback information usingthe single feedback signal in the receiving end. For example, when thereceiving end transmits to the transmitting end the HARQ feedbackinformation of four packets using the single feedback signal, the packetindex includes 2 bits.

Hereafter, it is assumed that the wireless communication system uses theG3PP LTE standard. Accordingly, it is assumed that the controlinformation of the transmitting end for notifying whether the packet istransmitted to the receiving end indicates the DCI transmitted over thePDCCH, and the packet is transmitted over a Physical Downlink ShARedChannel (PDSCH). Also, the receiving end is assumed to transmit the HARQfeedback information of four packets to the transmitting end using thefeedback signal.

FIG. 5 illustrates a method for retransmitting the packet in thewireless communication system according to one exemplary embodiment ofthe present invention.

As shown in FIG. 5, a transmitting end 500 sequentially transmits apacket 0, a packet 1, a packet 2, a packet 3, and a packet 4 to areceiving end 510 over the PDSCH in steps 521 through 529. In so doing,the transmitting end 500 transmits the packet index of each packet tothe receiving end 510 using the DCI transmitted through the PDCCH. Forexample, when transmitting the packet 0, the transmitting end 500transmits the DCI including a packet identifier ‘00’ of the packet 0 tothe receiving end 510 over the PDCCH in step 521. When transmitting thepacket 1, the transmitting end 500 transmits the DCI including thepacket identifier ‘01’ of the packet 1 to the receiving end 510 over thePDCCH in step 523. Also, when transmitting the packet 2, thetransmitting end 500 transmits the DCI including the packet identifier‘10’ of the packet 2 to the receiving end 510 over the PDCCH in step525. When transmitting the packet 3, the transmitting end 500 transmitsthe DCI including the packet identifier ‘11’ of the packet 3 to thereceiving end 510 over the PDCCH in step 527. Next, when transmittingthe packet 4, the transmitting end 500 transmits the DCI including thepacket identifier ‘00’ of the packet 4 to the receiving end 510 over thePDCCH in step 529. That is, the receiving end 510 transmits to thetransmitting end 500 the feedback signal including the HARQ feedbackinformation of the packets 0, 1, 2, and 3 and the HARQ feedbackinformation of the packet 4 using another feedback signal. Hence, thetransmitting end 500 sets the packet identifier of the packet 4 to ‘00’.

When receiving the four packets from the packet 0 to the packet 3 fromthe transmitting end 500 in steps 521 through 527, the receiving end 510transmits the HARQ feedback information of the four packets to thetransmitting end 500 using the single feedback signal after thetransmission time interval x TTIx 550 elapses from the reception of thepacket 3 in step 531.

The transmitting end 500 confirms the HARQ feedback information of thepackets 0, 1, 2, and 3 in the feedback signal provided from thereceiving end 510.

When the receiving end 510 requests to retransmit the packet 1 and thepacket 2, the transmitting end 500 retransmits the packet 1 and thepacket 2 to the receiving end 510 after the retransmission time intervaly TTIs 552 elapses from the reception of the feedback signal in steps533 and 537. When transmitting the DCI of the retransmitted packet, thetransmitting end 500 retransmits the packet 1 and the packet 2 to thereceiving end 510 at an arbitrary time after the retransmission timeinterval y TTIs 552 elapses from the reception of the feedback signal.In this case, the transmitting end 500 sequentially allocates the packetidentifiers regardless of the newly transmitted packet and theretransmitted packet. For example, when transmitting the packet 4 andthen retransmitting the packet 1, the transmitting end 500 transmits theDCI including the packet identifier ‘01’ of the packet 1 to thereceiving end 510 over the PDCCH in step 533. Next, when sequentiallytransmitting the packet 5 and the packet 2, the transmitting end 500transmits the DCI including the packet identifier ‘10’ of the packet 5to the receiving end 510 over the PDCCH in step 535, and transmits theDCI including the packet identifier ‘11’ of the packet 2 to thereceiving end 510 over the PDCCH in step 537.

When receiving the packet 4, the packet 1, the packet 5, and the packet2 in steps 529 and 533 through 537, the receiving end 510 transmits theHARQ feedback information of the four packets to the transmitting end500 using the single feedback signal after the transmission timeinterval x TTIx 550 elapses from the reception of the packet 2 in step539.

In this embodiment, the transmitting end 500 transmits the controlinformation DCI of the retransmitted packet to the receiving end 501.

In another embodiment, when not transmitting the control information ofthe retransmitted packet to the receiving end 501, the transmitting end500 transmits the retransmitted packet to the receiving end 510 as shownin FIG. 6.

FIG. 6 illustrates a method for retransmitting the packet in thewireless communication system according to another exemplary embodimentof the present invention.

As shown in FIG. 6, a transmitting end 600 sequentially transmits apacket 0, a packet 1, a packet 2, a packet 3, and a packet 4 to areceiving end 610 over the PDSCH in steps 621 through 629. In so doing,the transmitting end 600 transmits the packet index of each packet tothe receiving end 610 using the DCI transmitted through the PDCCH. Forexample, the transmitting end 600 transmits the DCI including the packetidentifier ‘00’ of the packet 0 to the receiving end 610 over the PDCCHin step 621, and transmits the DCI including the packet identifier ‘01’of the packet 1 to the receiving end 610 over the PDCCH in step 623.Also, the transmitting end 600 transmits the DCI including the packetidentifier ‘10’ of the packet 2 to the receiving end 610 over the PDCCHin step 625, and transmits the DCI including the packet identifier ‘11’of the packet 3 to the receiving end 610 over the PDCCH in step 627.Next, when transmitting the packet 4, the transmitting end 600 transmitsthe DCI including the packet identifier ‘00’ of the packet 4 to thereceiving end 610 over the PDCCH in step 629. That is, the receiving end610 transmits to the transmitting end 600 the feedback signal includingthe HARQ feedback information of the packets 0, 1, 2, and 3 and the HARQfeedback information of the packet 4 using another feedback signal.Hence, the transmitting end 600 sets the packet identifier of the packet4 to ‘00’.

When receiving the four packets from the packet 0 to the packet 3 fromthe transmitting end 600 in steps 621 through 627, the receiving end 610transmits the HARQ feedback information of the four packets to thetransmitting end 600 using the single feedback signal after thetransmission time interval x TTIx 650 elapses from the reception of thepacket 3 in step 631.

The transmitting end 600 confirms the HARQ feedback information of thepackets 0, 1, 2, and 3 in the feedback signal provided from thereceiving end 610.

When the receiving end 610 requests to retransmit the packet 1 and thepacket 2, the transmitting end 600 retransmits the packet 1 and thepacket 2 to the receiving end 610 after the retransmission time intervaly TTIs 652 elapses from the reception of the feedback signal. In sodoing, when not transmitting the DCI of the retransmitted packet, thetransmitting end 600 sequentially retransmits the packet 1 and thepacket 2 to the receiving end 610 after the retransmission time intervaly TTIs 652 elapses from the reception of the feedback signal. In thiscase, the transmitting end 600 sequentially allocates the packetidentifiers regardless of the newly transmitted packet and theretransmitted packet. For example, when transmitting the packet 4 andthen retransmitting the packet 1 and the packet 2, the transmitting end600 sets the packet identifier ‘01’ of the packet 1 and sets the packetidentifier ‘10 of the packet 2. Hence, when retransmitting the packet 1and the packet 2 and then transmitting the packet 5, the transmittingend 600 transmits the DCI including the packet identifier ‘11’ of thepacket 5 to the receiving end 610 over the PDCCH in step 637.

When receiving the packet 4, the packet 1, the packet 2, and the packet5 in steps 629 and 633 through 637, the receiving end 610 transmits theHARQ feedback information of the four packets to the transmitting end600 using the single feedback signal after the transmission timeinterval x TTIs 650 elapses from the reception of the packet 5 in step639.

As such, when the transmitting end transmits the control informationincluding the packet index to the receiving end, the receiving end canrecognize the presence of the unreceived packet unless the packetindexes of the packets received from the transmitting end is sequential.In this case, the receiving end transmits the unreceived packetinformation to the transmitting end in order to prevent the transmissiontime error of the feedback signal.

As such, when the receiving end includes and transmits the HARQ feedbackinformation of the N_(AG)-ary packets using the feedback signal, thereceiving end does not transmit the HARQ feedback information to thetransmitting end until the N_(AG)-ary packets are received. Hence, whenreceiving N_(AG)-1-ary packets and then receiving no N_(AG)-th packetfor a long time, the receiving end may continuously maintain the HARQprocess for the N_(AG)-1-ary packets because it does not transmit theHARQ feedback information of the N_(AG)-1-ary packets.

To address this, when receiving the first packet and then not receivingthe last packet to transmit the HARQ feedback information within areference time z TTIs as shown in FIG. 7, the receiving end of thewireless communication system transmits the HARQ feedback information ofat least one packet received so far, to the transmitting end using thefeedback signal.

FIG. 7 illustrates a method for transmitting the HARQ feedbackinformation in the wireless communication system according to anotherexemplary embodiment of the present invention.

As shown in FIG. 7, a transmitting end 700 sequentially transmits apacket 0 and a packet 1 to a receiving end 710 over the PDSCH in steps721 through 723. In so doing, the transmitting end 700 transmits thepacket index of each packet to the receiving end 710 using the DCItransmitted through the PDCCH. For example, the transmitting end 700transmits the DCI including the packet identifier ‘00’ of the packet 0to the receiving end 710 over the PDCCH in step 721, and transmits theDCI including the packet identifier ‘01’ of the packet 1 to thereceiving end 710 over the PDCCH in step 723.

When receiving the packet 0 of the packet identifier ‘00’ in step 721,the receiving end 710 drives a first timer for determining the HARQfeedback transmission time. In so doing, when receiving the packet ofthe packet identifier ‘00’, the receiving end 710 resets the firsttimer.

When not receiving the N_(AG)-ary packets to transmit the HARQ feedbackinformation until the driving time z TTIs 730 of the first timer expiresin step 725, the receiving end 710 transmits the HARQ feedbackinformation of the packet 0 and the packet 1 received, to thetransmitting end 700 using the single feedback signal after thetransmission time interval x TTIs 740 elapses from the expiration (step725) of the first timer, in step 729.

After transmitting the packet 0 of the packet identifier ‘00’, thetransmitting end 700 drives a second timer for recognizing the HARQfeedback transmission time of the receiving end 710. In so doing, whentransmitting the packet of the packet identifier ‘00’, the transmittingend 700 resets the second timer.

When the driving time z TTIs 730 of the second timer expires, thetransmitting end 700 recognizes that the receiving end 710 transmits theHARQ feedback information of the packets from the packet of the packetidentifier ‘00’ to the packet transmitted so far. Hence, thetransmitting end 700 sets the packet identifier ‘00’ of the packet 2transmitted after the expiration of the second timer driving time andtransmits to the receiving end 710 in step 727. At this time, thetransmitting end 700 resets the second timer.

FIG. 8 illustrates a method for transmitting the HARQ feedbackinformation in the receiving end according to another exemplaryembodiment of the present invention.

Referring to FIG. 8, the receiving end determines whether the packet isreceived from the transmitting end in step 801.

When not receiving the packet from the transmitting end, the receivingend determines whether the driving of the first timer for determiningthe HARQ feedback transmission time expires in step 815.

By contrast, when receiving the packet from the transmitting end, thereceiving end determines whether the received packet is the first packetfor the HARQ feedback in step 803. For example, the receiving enddetermines whether the packet index of the received packet is ‘00’.

When not receiving the first packet for the HARQ feedback, the receivingend updates (NRE++) the number of the packet receptions NRE in step 807.Here, the number of the packet receptions is the variable fordetermining whether to transmit the HARQ feedback and can be set to 0 asthe initial value.

By contrast, when receiving the first packet for the HARQ feedback, thereceiving end resets the first timer in step 805.

Next, the receiving end updates (NRE++) the number of the packetreceptions NRE in step 807.

After updating the number of the packet receptions, the receiving enddetermines whether the number of the packet receptions is greater thanor equal to the number of the feedback packets N_(AG) to determinewhether to transmit the HARQ feedback information in step 809.

When the number of the packet receptions is smaller than the number ofthe feedback packets N_(AG) (NRE<N_(AG)), the receiving end recognizesno HARQ feedback information transmission. Hence, the receiving enddetermines whether the driving time of the first timer expires in step815.

When the driving time of the first timer does not expire, the receivingend determines whether the packet is received from the transmitting endin step 801.

By contrast, when the driving of the first timer expires, the receivingend recognizes to transmit the HARQ feedback information for the packetsfrom the first packet for the HARQ feedback to at least one packetcurrently received. Hence, the receiving end determines whether thetransmission time arrives in step 811. For example, the receiving enddetermines whether the transmission time interval x TTIs 740 elapsesfrom the expiration of the first timer driving in step 725 as shown inFIG. 7. At this time, the receiving end initializes the number of thepacket receptions to determine whether to transmit the next HARQfeedback information.

By contrast, when the number of the packet receptions is greater than orequal to the number of the feedback packets N_(AG) (NRE≧N_(AG)) in step809, the receiving end recognizes to transmit the HARQ feedbackinformation. Hence, the receiving end determines whether thetransmission time arrives in step 811. For example, the receiving end210 determines whether the transmission time interval x TTIs 220 elapsesfrom the reception of the N_(AG)-th packet as shown in FIG. 2. At thistime, the receiving end initializes the number of the packet receptionsto determine whether to transmit the next HARQ feedback information.

When the transmission time arrives, the receiving end transmits the HARQfeedback information of at least one packet to the transmitting endusing the single feedback signal in step 813. For example, when thedriving of the first timer expires, the receiving end transmits the HARQfeedback information of the packets from the first packet for the HARQfeedback to the at least one packet from currently received, to thetransmitting end using the single feedback signal. For example, whenreceiving N_(AG)-ary packets, the receiving end transmits the HARQfeedback information of the N_(AG)-ary packets to the transmitting end200 using the single feedback signal.

Next, the receiving end finishes this algorithm.

As such, when the receiving end transmits the HARQ feedback informationof at least one packet using the single feedback signal, thetransmitting end can confirm the HARQ feedback information of at leastone packet as shown in FIG. 9.

FIG. 9 illustrates a method for confirming the HARQ feedback informationin the transmitting end according to another exemplary embodiment of thepresent invention.

Referring to FIG. 9, the transmitting end determines whether to transmitthe packet to the receiving end in step 901.

When the receiving end does not transmit the packet, the transmittingend determines whether the driving of the second timer for recognizingthe HARQ feedback transmission time of the receiving end expires in step917.

By contrast, when transmitting the packet to the receiving end, thetransmitting end determines whether the packet transmitted to thereceiving end is the first packet for the HARQ feedback of the receivingend in step 903. For example, the transmitting end determines whetherthe packet index of the packet transmitted to the receiving end is ‘00’

When the packet transmitted to the receiving end is not the first packetfor the HARQ feedback, the transmitting end updates (NTR++) the numberof the packet transmissions NTR in step 907. Here, the number of thepacket transmissions is the variable for confirming the HARQ feedbacktransmission time of the receiving end, and can be set to 0 as theinitial value.

When the packet transmitted to the receiving end is the first packet forthe HARQ feedback, the receiving end resets the second timer in step905.

Next, the receiving end updates (NTR++) the number of the packettransmissions NTR in step 907.

After updating the number of the packet transmissions, the transmittingend determines whether the number of the packet transmissions is greaterthan or equal to the number of the feedback packets N_(AG) to confirmthe HARQ feedback information transmission time of the receiving end instep 909.

When the number of the packet transmissions is smaller than the numberof the feedback packets N_(AG) (NTR<N_(AG)), the transmitting endrecognizes no HARQ feedback information transmission of the receivingend. Hence, the transmitting end determines whether the driving of thesecond timer expires in step 917.

When the driving of the second timer does not expire, the transmittingend determines whether to transmit the packet to the receiving end instep 901.

By contrast, when the driving of the second timer expires, thetransmitting end recognizes to transmit the HARQ feedback informationfor the packets from the first packet for the HARQ feedback to the atleast one packet currently received from the receiving end. Hence, thetransmitting end initializes the packet index in step 911. That is,after the driving of the second timer expires, the transmitting end setsthe packet identifier of the packet transmitted first or retransmitted,to ‘00’. In so doing, the transmitting end initializes the number of thepacket transmissions to determine the transmission time of the next HARQfeedback information of the receiving end.

Meanwhile, when the number of the packet transmissions is greater thanor equal to the number of the feedback packets N_(AG) (NTR≧N_(AG)) instep 909, the transmitting end recognizes that the receiving endtransmits the HARQ feedback information after the transmission timeinterval. Hence, the transmitting end initializes the packet index instep 911. That is, the transmitting end sets the packet identifier ofthe packet transmitted next or retransmitted, to ‘00’. In so doing, thetransmitting end initializes the number of the packet transmissions todetermine the transmission time of the next HARQ feedback information ofthe receiving end.

Next, the transmitting end determines whether the feedback signal isreceived from the receiving end in step 913.

When receiving the feedback signal from the receiving end, thetransmitting end confirms the HARQ feedback information of at least onepacket in the feedback signal received from the receiving end in step915. For example, when the driving of the second timer expires, thetransmitting end confirms the HARQ feedback information of the firstpacket for the HARQ feedback and at least one packet transmitted to thereceiving end until the driving of the second timer expires, in thefeedback signal received from the receiving end. For example, when thedriving of the second timer does not expire, the transmitting endconfirms the HARQ feedback information of the N_(AG)-ary packets in thefeedback signal received from the receiving end.

Next, the transmitting end finishes this algorithm. Although it is notillustrated, the transmitting end may retransmit at least one packet byconsidering the HARQ feedback information of at least one packettransmitted to the receiving end as shown in FIG. 4.

As such, the receiving end can transmit the HARQ feedback information ofthe plurality of the packets to the transmitting end through the singlefeedback signal transmission and thus reduce resource waste according tothe HARQ feedback. However, the receiving end needs to accurately obtainthe packet transmission of the transmitting end and thus can transmitthe HARQ feedback information of the plurality of the packets to thetransmitting end through the single feedback signal transmission.

Thus, the wireless communication system may selectively use a pluralityof feedback modes by considering at least one of a servicecharacteristic and a channel characteristic. In this case, thetransmitting end can control the feedback mode of the receiving end asshown in FIG. 10. Hereafter, it is assumed that the transmitting endchanges the feedback mode from a first feedback mode to a secondfeedback mode. However, the transmitting end may change the feedbackmode from the second feedback mode to the first feedback mode in thesame manner. Here, the first feedback mode is assumed to indicate afeedback mode of the receiving end for transmitting the HARQ feedbackinformation of each packet to the transmitting end, and the secondfeedback mode is assumed to indicate a feedback mode of the receivingend for transmitting the HARQ feedback information of the multiplepackets to the transmitting end using the single feedback signal.

FIG. 10 illustrates a method for switching the feedback mode in thetransmitting end according to an exemplary embodiment of the presentinvention.

Referring to FIG. 10, the transmitting end receives the HARQ feedbackinformation of the packet transmitted to the receiving end, in the firstfeedback mode. For example, the transmitting end receives the HARQfeedback information of each packet transmitted to the receiving end,from the receiving end.

Next, the transmitting end determines whether to change the feedbackmode in step 1003. For example, the transmitting end determines whetherto change the feedback mode by considering at least one of the servicecharacteristics provided to the receiving end and the channelcharacteristic in relation to the receiving end.

When not changing the feedback mode, the transmitting end receives theHARQ feedback information of the packet transmitted to the receivingend, in the first feedback mode in step 1001.

By contrast, when changing the feedback mode, the transmitting endconfirms an operation variable for the second feedback mode in step1005. For example, the transmitting end determines the operationvariable for the second feedback mode including at least one of thenumber of the packets of the receiving end for carrying the HARQfeedback information at one time, the transmission time interval x TTIsof the receiving end, the retransmission time interval y TTIs of thetransmitting end, and a feedback mode change time.

After confirming the operation variable for the second feedback mode,the transmitting end transmits a feedback mode change request signal tothe receiving end in step 1007. In so doing, the feedback mode changerequest signal includes the operation variable for the second feedbackmode confirmed in step 1005.

In step 1009, the transmitting end determines whether the feedback modechange time arrives in step 1009.

When the feedback mode change time arrives, the transmitting endswitches to the second feedback mode in step 1011. Hence, thetransmitting end can confirm the HARQ feedback information of themultiple packets in the feedback signal received from the receiving endas shown in FIG. 3 or FIG. 9.

Next, the transmitting end finishes this algorithm.

As such, when the transmitting end controls the feedback mode of thereceiving end, the receiving end can change the feedback mode as shownin FIG. 11.

FIG. 11 illustrates a method for switching the feedback mode in thereceiving end according to an exemplary embodiment of the presentinvention.

Referring to FIG. 11, the receiving end receives the HARQ feedbackinformation of the packet received from the transmitting end accordingto the first feedback mode in step 1101. For example, the receiving endtransmits the HARQ feedback information of each packet received from thetransmitting end, to the transmitting end.

In step 1103, the receiving end determines whether the feedback modechange request signal is received from the transmitting end.

When receiving the feedback mode change request signal from thetransmitting end, the receiving end confirms the operation variable forthe second feedback mode in the feedback mode change request signal instep 1105. Here, the operation variable for the second feedback modeincludes at least one of the number of the packets of the receiving endfor carrying the HARQ feedback information at one time, the transmissiontime interval x TTIs of the receiving end, the retransmission timeinterval y TTIs of the transmitting end, and the feedback mode changetime.

After confirming the operation variable for the second feedback mode,the receiving end determines whether a feedback mode change time arrivesin step 1107.

When the feedback mode change time arrives, the receiving end switchesto the second feedback mode in step 1109. Hence, the receiving endtransmits the HARQ feedback information of the N_(AG)-ary packets to thetransmitting end using the single feedback signal as shown in FIG. 2 orFIG. 8.

Next, the receiving end finishes this algorithm.

FIG. 12 is a block diagram of the transmitting end according to anexemplary embodiment of the present invention.

As shown in FIG. 12, the transmitting end includes a duplexer 1200, areceiver 1210, a controller 1220, and a transmitter 1230.

The duplexer 1200 transmits the transmit signal output from thetransmitter 1230 over an antenna and provides the receive signal fromthe antenna to the receiver 1210 according to the duplexing.

The receiver 1210 processes the packet and the control informationprovided from the receiving end by converting a radio frequency signalprovided from the duplexer 1200 to a baseband signal. For example, thereceiver 1210 can include an RF processer 1211, an Analog/DigitalConvertor (ADC) 1213, an OFDM demodulator 1215, a decoder 1217, and amessage processor 1219.

The RF processor 1211 converts the radio frequency signal fed from theduplexer 1200 to a baseband analog signal. The ADC 1213 converts theanalog signal provided from the RF processor 1211 to digital sampledata.

The OFDM demodulator 1215 converts time-domain sample data provided fromthe ADC 1213 to frequency-domain data through Fast Fourier Transform(FFT).

The decoder 1217 selects data of subcarriers to actually receive fromthe frequency-domain data provided from the OFDM demodulator 1215. Next,the decoder 1217 demodulates and decodes the selected data at a presetmodulation level (MCS level).

The message processor 1219 confirms the control information in thesignal provided from the decoder 1217 and sends to the controller 1220.For example, the message processor 1219 sends the feedback signalprovided from the receiving end to the controller 1220.

The controller 1220 controls to transmit the packet to the receivingend. In so doing, the controller 1220 allocates the packet index to eachpacket by considering the number of the packets transmitted to thereceiving end as shown in FIG. 5 or FIG. 6.

The controller 1220 confirms the HARQ feedback information of themultiple packets in the feedback signal provided from the messageprocessor 1219. When there is the packet requested by the receiving endto retransmit, the controller 1220 controls to retransmit thecorresponding packet. In so doing, the controller 1220 controls toretransmit the packet after the retransmission time interval y TTIselapses from the reception of the feedback signal. For example, whenretransmitting a plurality of packets using the synchronous HARQ, thecontroller 1220 sequentially retransmits the corresponding packets inthe preset retransmission order after the retransmission time interval yTTIs passes from the reception of the feedback signal. In so doing, thecontroller 1220 may not transmit the control message for theretransmitted packets. For example, when retransmitting a plurality ofpackets using the asynchronous HARQ, the controller 1220 retransmits thecorresponding packets at an arbitrary time after the retransmission timeinterval y TTIs elapses from the reception of the feedback signal. In sodoing, the controller 1220 controls a message generator 1231 to transmitthe control message including the identification information of theretransmitted packets to the receiving end.

The transmitter 1230 converts the packet and the control information totransmit to the receiving end, to an RF signal, and transmits to theoutside via the duplexer 1220 and the antenna. For example, thetransmitter 1230 can include the message generator 1231, an encoder1233, an OFDM modulator 1235, a Digital/Analog Convertor (DAC) 1237, andan RF processor 1239.

The message generator 1231 generates the control message under thecontrol of the controller 1220. For example, the message generator 1231generates the feedback mode change request signal including theoperation variable for the feedback mode change under the control of thecontroller 1220. For example, the message generator 1231 generates thecontrol information including the packet index.

The encoder 1233 encodes and modulates the transmit packet and thecontrol message generated by the message generator 1231 at thecorresponding modulation level (MCS level).

The OFDM modulator 1235 converts time-domain sample data provided fromthe encoder 1233 to time-domain sample data (OFDM symbol) throughInverse Fast Fourier Transform (IFFT).

The DAC 1237 converts the sample data provided from the OFDM modulator1235 to the analog signal. The RF processor 1239 converts the basebandanalog signal provided from the DAC 837 to the radio frequency signal.

Although it is not depicted, the transmitting end can further include asecond timer for recognizing the HARQ feedback transmission time of thereceiving end. The second timer is reset under the control of thecontroller 1220 when the transmitting end transmits the first packet forthe HARQ feedback of the receiving end. When the driving time of thesecond timer expires, the controller 1220 recognizes that the receivingend transmits the HARQ feedback of the packets from the first packet forthe HARQ feedback of the receiving end to the packet currentlytransmitted to the receiving end. Hence, the controller 1220 sets thepacket identifier of the packet transmitted first after the driving timeof the second timer expires, to ‘00’. Here, the packet identifier ‘00’indicates the first packet for the HARQ feedback of the receiver.

FIG. 13 is a block diagram of the receiving end according to anexemplary embodiment of the present invention.

As shown in FIG. 13, the receiving end includes a duplexer 1330, areceiver 1310, a controller 1320, and a transmitter 1330.

The duplexer 1300 transmits the transmit signal provided from thetransmitter 1330 over an antenna and provides the receive signal fromthe antenna to the receiver 1310 according to the duplexing.

The receiver 1310 processes the packet and the control information fromthe transmitting end by converting the radio frequency signal providedfrom the duplexer 1300 to a baseband signal. For example, the receiver1310 can include an RF processer 1311, an Analog/Digital Convertor (ADC)1313, an OFDM demodulator 1315, a decoder 1317, and a message processor1319.

The RF processor 1311 converts the radio frequency signal provided fromthe duplexer 1300 to the baseband analog signal. The ADC 1313 convertsthe analog signal provided from the RF processor 1311 to digital sampledata.

The OFDM demodulator 1315 converts time-domain sample data provided fromthe ADC 1313 to frequency-domain data through the FFT.

The decoder 1317 selects data of subcarriers to actually receive fromthe frequency-domain data provided from the OFDM demodulator 1315. Next,the decoder 1317 demodulates and decodes the selected data at the presetmodulation level (MCS level).

The message processor 1319 confirms the control information in thesignal provided from the decoder 1317 and sends to the controller 1320.For example, the message processor 1319 confirms and sends the feedbackmode change request signal provided from the transmitting end, to thecontroller 1320.

The controller 1320 controls overall operation of the receiving end. Forexample, the controller 1320 controls a feedback controller 1321 tochange the feedback mode according to the feedback mode change requestsignal provided from the transmitting end as shown in FIG. 11.

The feedback controller 1321 controls not to transmit the HARQ feedbackinformation until the N_(AG)-ary packets are received. When receivingthe N_(AG)-ary packets, the feedback controller 1321 controls totransmit the HARQ feedback information of the N_(AG)-ary packets to thetransmitting end using the single feedback signal after the transmissiontime interval x TTIs passes from the reception of the N_(AG)-th packetas shown in FIG. 3.

When the packet indexes of the packets received from the transmittingend are not sequential, the feedback controller 1321 recognizes that thepackets transmitted by the transmitting end include the unreceivedpacket. In this case, the feedback controller 1321 controls to transmitthe unreceived packet information to the transmitting end in order toprevent the transmission time error of the feedback signal.

When the receiving end does not receive the last packet to transmit theHARQ feedback information within the reference time z TTIs after thefirst packet for transmitting the HARQ feedback information is received,the feedback controller 1321 controls to transmit the HARQ feedbackinformation of the packets from the first packet to at least one packetreceived so far, to the transmitting end using the feedback signal asshown in FIG. 8.

The transmitter 1330 converts the packet and the control information totransmit to the transmitting end, to the radio frequency signal, andtransmits to the outside via the duplexer 1300 and the antenna. Forexample, the transmitter 1330 can include the message generator 1331, anencoder 1333, an OFDM modulator 1335, a DAC 1337, and an RF processor1339.

The message generator 1331 generates the control message under thecontrol of the controller 1320. For example, the message generator 1331generates the feedback signal including the HARQ feedback information ofthe N_(AG)-ary packets under the control of the controller 1320.

The encoder 1333 encodes and modulates the transmit packet and thecontrol message generated by the message generator 1331 at thecorresponding modulation level (MCS level).

The OFDM modulator 1335 converts time-domain sample data provided fromthe encoder 1333 to time-domain sample data (OFDM symbol) through theIFFT.

The DAC 1337 converts the sample data provided from the OFDM modulator1335 to the analog signal. The RF processor 1339 converts the basebandanalog signal provided from the DAC 1337 to the radio frequency signal.

Although it is not depicted, the receiving end can further include anerror checker for determining whether the packet received from thetransmitting end has an error, and a first timer for determining theHARQ feedback transmission time. The first timer is reset under thecontrol of the controller 1320 when the first packet for the HARQfeedback is received from the transmitting end. When the driving time ofthe first timer expires, the feedback controller 1321 determines totransmit to the transmitting end the HARQ feedback of the packets fromthe first packet for the HARQ feedback to the packet received so far.

As set forth above, the receiving end of the wireless communicationsystem transmits the HARQ feedback information of the multiple packetsto the transmitting end using the single feedback signal. Thus, thereceiving end can lower the power consumption in the HARQ feedbackinformation transmission by reducing the time resource for transmittingthe HARQ feedback information.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims and their equivalents.

1. A method for transmitting Hybrid Automatic Repeat request (HARQ)feedback information in a receiving end of a wireless communicationsystem, the method comprising: confirming the number of packets receivedfrom a transmitting end; and when receiving a reference number ofpackets from the transmitting end, transmitting to the transmitting enda feedback signal comprising HARQ feedback information for the referencenumber of the packets.
 2. The method of claim 1, wherein the confirmingof the number of the packets comprises: confirming the number of packetsnot transmitting the HARQ feedback information to the transmitting endamong the packets received from the transmitting end.
 3. The method ofclaim 1, wherein the transmitting to the transmitting end comprises:when receiving the reference number of the packets, determining whethera first reference time passes from reception of a last packet among thereference number of the packets; and after the first reference time,transmitting the feedback signal comprising the HARQ feedbackinformation of the reference number of the packets, to the transmittingend.
 4. The method of claim 1, wherein the transmitting to thetransmitting end comprises: transmitting the feedback signal indicatingthe HARQ feedback information of each of the reference number of thepackets, to the transmitting end.
 5. The method of claim 1, furthercomprising: when not receiving the reference number of the packets,determining whether a second reference time passes from reception of afirst packet for transmitting the HARQ feedback information; and whenthe second reference time passes from the reception of the first packet,transmitting the feedback signal comprising the HARQ feedbackinformation of at least one packet received from the transmitting end,to the transmitting end.
 6. The method of claim 1, further comprising:when receiving feedback mode change information from the transmittingend before confirming the number of the packets, confirming an operationvariable for the feedback of the HARQ feedback information in thefeedback mode change information.
 7. The method of claim 6, wherein theoperation variable comprises at least one of a reference number for theHARQ feedback, a first reference time, a reference time forretransmission of the transmitting end, and a feedback mode change time.8. (canceled)
 9. A method for confirming Hybrid Automatic Repeat request(HARQ) feedback information in a transmitting end of a wirelesscommunication system, the method comprising: transmitting a packet to areceiving end; and when receiving a feedback signal from the receivingend, confirming HARQ feedback information for a reference number ofpackets in the feedback signal.
 10. The method of claim 9, wherein thetransmitting of the packet comprises: transmitting the packet andcontrol information comprising a packet index of the packet, to thereceiving end, wherein the packet index indicates an index indicatingthe reference number of the packets.
 11. The method of claim 9, furthercomprising: before transmitting the packet to the receiving end, whenchanging a feedback mode for transmitting the HARQ feedback informationof the receiving end, transmitting feedback mode change informationcomprising an operation variable for feedback of the HARQ feedbackinformation, to the receiving end.
 12. The method of claim 11, whereinthe operation variable comprises at least one of a reference number, areference time for transmitting the feedback of the receiving end, areference time for retransmission of the transmitting end, and afeedback mode change time.
 13. The method of claim 11, furthercomprising: determining whether to change the feedback mode byconsidering at least one of a service characteristic provided to thereceiving end and a channel characteristic in relation to the receivingend.
 14. The method of claim 1, wherein the HARQ feedback informationcomprises at least one of ACK indicating successful packet reception,NACK indicating packet reception failure, and Discontinuous Transmission(DTX) indicating no packet reception confirmed.
 15. (canceled)
 16. Anapparatus for a receiving end in a wireless communication system, theapparatus comprising: a receiver configured to receive packets; acontroller configured when the receiver receives the packets fromtransmitting end, to confirm the number of packets received from atransmitting end; and a transmitter configured to, when receiving areference number of packets from the transmitting end, transmit to thetransmitting end a feedback signal comprising Hybrid Automatic RepeatreQuest (HARQ) feedback information for the reference number of thepackets, and to transmit the feedback signal to the transmitting end.17. The apparatus of claim 16, wherein the controller is furtherconfigured to confirm the number of packets not transmitting the HARQfeedback information to the transmitting end among the packets receivedfrom the transmitting end.
 18. The apparatus of claim 16, wherein thecontroller is further configured to, when receiving the reference numberof the packets, after a first reference time from reception of a lastpacket among the reference number of the packets, transmit the feedbacksignal comprising the HARQ feedback information of the reference numberof the packets, to the transmitting end.
 19. The apparatus of claim 16,wherein the transmitter is further configured to transmit the feedbacksignal indicating the HARQ feedback information of each of the referencenumber of the packets, to the transmitting end.
 20. The apparatus ofclaim 16, wherein the controller is further configured to, when notreceiving the reference number of the packets, after a second referencetime from reception of a first packet for transmitting the HARQ feedbackinformation, transmit the feedback signal comprising the HARQ feedbackinformation of at least one packet received from the transmitting end,to the transmitting end.
 21. The apparatus of claim 16, wherein thecontroller is further configured to, when the receiver receives feedbackmode change information from the transmitting end, transmit the feedbacksignal comprising the HARQ feedback information of the reference numberof the packets, to the transmitting end by considering an operationvariable information in the feedback mode change information.
 22. Theapparatus of claim 21, wherein the operation variable comprises at leastone of a reference number for the HARQ feedback, a first reference time,a reference time for retransmission of the transmitting end, and afeedback mode change time.
 23. An apparatus for a transmitting end in awireless communication system, the apparatus comprising: a transmitterconfigured to transmit a packet to a receiving end; a receiverconfigured to receive a signal from the receiving end; a controllerconfigured to, when the receiver receives a feedback signal from thereceiving end, confirm Hybrid Automatic Repeat reQuest (HARQ) feedbackinformation for a reference number of packets in the feedback signal.24. The apparatus of claim 23, wherein the transmitter is furtherconfigured to transmit the packet and control information comprising apacket index of the packet, to the receiving end, and the packet indexindicates an index indicating the reference number of the packets. 25.The apparatus of claim 23, wherein the controller is further configuredto determine whether to change a feedback mode by considering at leastone of a service characteristic provided to the receiving end and achannel characteristic in relation to the receiving end.
 26. Theapparatus of claim 25, wherein the controller is further configured to,when changing the feedback mode, transmit feedback mode changeinformation comprising an operation variable for feedback of the HARQfeedback information, to the receiving end.
 27. The apparatus of claim26 wherein the operation variable comprises at least one of a referencenumber, a reference time for transmitting the feedback of the receivingend, a reference time for retransmission of the transmitting end, and afeedback mode change time.
 28. The apparatus of claim 23, wherein theHARQ feedback information comprises at least one of ACK indicatingsuccessful packet reception, NACK indicating packet reception failure,and Discontinuous Transmission (DTX) indicating no packet receptionconfirmed.